This invention relates to a synchronizing system which can have application in facsimile transmission apparatus or magnetic recording and reproducing apparatus to obtain synchronization of the image signals with synchronizing signals.
Devices have already been known for use with, say, facsimile transmission apparatus in which a plurality of read-out heads arranged peripherally of a rotary drum and disposed equidistantly from one another are used for successively scanning an objective or a document to produce image signals. In such devices, the image signals corresponding to a plurality of lines scanned by the read-out heads are produced while the rotary drum makes one revolution, and at the same time a plurality of marks provided on the rotary drum to correspond to the plurality of read-out heads produce synchronizing sygnals which are read by the read-out heads, whereby a synchronizing signal can be produced which corresponds to either the starting portion or the terminating portion of the image signal produced by scanning one line.
In such devices, the phase of the starting portion or the terminating portion of the image signal produced by scanning one line and the phase of the synchronizing signal produced are determined by the relative positions of the plurality of synchronizing signals and the plurality of head-out heads on the rotary drum. If ordinary machining is tolerated in production, it will be impossible to obtain accurate relative positions for the heads and the synchronizing signals, with the result that the image signals will be out of phase with the synchronizing signals. Thus the images received by facsimile receiving apparatus are blurred.